148 THE NEW KNOWLEDGE. 



tain elements such as uranium, thorium, radium, with as 

 much right to the title of elements as any other, break 

 down or become transmuted into certain other elements 

 also, with a perfect right to the title. Certain of these 

 transmuted elements have but a brief span of existence, 

 and are but half-way stages to some final products of de- 

 composition. The following table shows us the duration of 

 existence of some of these transmuted elements: 



NAME OF TRANSMUTED ELEMENT. TIME TAKEN FOB HALF OF BODY 



TO UNDERGO CHANGE. 



Uranium X, 22 days. 

 Thorium X, 4 days. 



Thorium emanation, 1 minute. 



Radium emanation, 3.7 days. 



Radium emanation X, 1st change, 3 minutes. 



2d change, 21 minutes. 



3d change, 28 minutes. 



4th change, 200 years? 



Final product. 



We know this elemental transmutation only as it is re- 

 vealed by radio-activity, the power these elements possess 

 of emitting penetrating rays. The instruments by which 

 these changes are traced are hundreds of thousands of times 

 more sensitive than any known mechanism, but their re- 

 sults are definite and reliable. The amount of elemental 

 transmutation taking place at any one instant is exceed- 

 ingly small, but it is actual. It .is, at this day, beyond the 

 power of man to aid or hinder this process. It seems in- 

 evitable. 



Twentieth Century Science has this work to do. To use the 

 prescient words of Faraday nearly a century old: "To de- 



